Airplane Scouting 



Airplaones have come into increaeingly common use for locating fish in various parts of 

 the world. Harrison (1931) reported that planes were successfully used for locating schools of 

 menhaden off the North Carolina coast. Gushing et al. (1952) discussed the use of planes and 

 helicopters, particularly in the Americaji tuna fishery, where they reported that schools of tuna 

 nnore than 20 nniles away have been spotted fronn the air and that under usual conditions much 

 more can be seen from the plane above altitudes of 600 feet. However, Sette (1949) felt that the 

 method was not satisfactory for locating pilchard off California, where the scouting was done 

 by day, the fishing by night. Blackburn and Tubb (1950) found that planes aided in exploratory 

 work in Australia, but the observations left much to be desired over waters where many different 

 species were schooling. Then, too, planes have been previously used for locating skipjack in 

 Hawaiian waters, although it was reported to us that the trials were not extensive enough to 

 demonstrate their value. Clearly, plane scouting was a likely method of locating skipjack and 

 we undertook to test it. 



Figure 2. --Track chart, GILBERT cruise 7, in February. 



Through the cooperation of 

 the United States Navy at Barbers 

 Point, Oahu, six flights were made 

 between November 14, 1952 and 

 June 15, 1953. These flights were 

 made in an amphibious PBY plane, 

 which was ideal for our aerial 

 scouting because it had a rela- 

 tively low cruising speed of approx- 

 imately 100 knots and it had large 

 blisters, where four observers 

 could conveniently be located, on 

 the fuselage just forward of the 

 tail assembly. 



Since this was our first 

 attempt at aerial scouting, the 

 scouting procedure was necessarily 

 modified several times before a 

 more standardized technique could 

 be developed. Following is a sum- 

 mary of the procedures employed: 



The first method was to have 

 each observer work independently 

 throughout the entire flight and re- 

 cord his own observations. This 

 method sometimes produced con- 

 fusing records in which it was 

 impossible to determine whether 

 two observers had recorded the 

 sanne object or whether they had 

 recorded separate objects at the 

 same time. 



An improved method was to 

 divide the observers into two teams, 

 placing a team of two on each side 

 of the plane. A member of each 

 team scanned fronn a point directly 

 below the plane to an angle of about 

 30 from vertical on one side, the 

 other outward from this point. 



